Pulling an all-nighter can make you feel completely drained, cranky, and out of sorts the next day, but can it also actually injure the brain? A new Swedish study published last Tuesday in the journal Sleep indicates that it might.

In the small study conducted in 15 healthy young men, the researchers measured blood levels of certain proteins associated with brain injuries like concussions after the men slept eight hours in a sleep lab and then were kept awake all night playing board games and watching movies. The researchers found that the blood protein levels were 20 percent higher after the men pulled an all-nighter compared to when they had a full night’s rest.